Managing battery life with auxiliary/dual battery

[rur42]

Ctek's article appeared in an aftermarket automotive industry publication. Of course their end game is to sell more Ctek analysers and chargers to workshops, so they in turn can sell more services and batteries to retail customers.

Of relevance to the Grenadier and Quartermaster community is this idea that the starter battery is working harder than the auxiliary battery because the batteries are isolated from each other electrically by the battery combiner (Smartpass 120S or a stripped down version). Functionally they have different load profiles and will therefore age differently. This might be an actual thing or I might be getting waterboarded by Ctek's Kool aid. In any case I'm a man of leisure (still not ready to say I'm retired) and I have time to ponder these things.

Early Grenadier owners will have accrued two years of life on their original battery/ies. I'm 20 months into mine. I'll take a guess that is maybe 40% of the expected service life for a wet cell battery with stop-start duties, perhaps a bit higher for diesel engines and colder climates. If Ctek are correct, the difference should be measurable by a comparison load test of both batteries. Ctek did say 'slight' to cover themselves.

I'll see if I can arrange some testing on my batteries. If it's a thing then we're more informed to do something, or nothing.

We don't normally consider this aspect in a conventional starter/main and house/2nd battery configuration because the 2nd battery is typically AGM or lithium and not interchangeable.

Managing the load on multi-battery setups is definitely a thing. Even with just a basic multiple batteries in parallel setup, with no ctek or combiner, if you don't wire them correctly both batteries will experience different loads and charge voltages. This can mess up your battery bank long term and was a big concern on my boat, where I'd go through many deep discharge and recharge cycles.

Not sure if this is really an issue with the grens. But since it wired through a combiner, the second battery is definitely experiencing reduce load, and lower charge voltage. Not by a whole lot, basically the resistance of the extra wiring.

 

[RYAustralia]

I recently read an article from Ctek on managing batteries in larger vehicles. See below. The context was 24v (2 x 12v) dual battery configurations.

There is an interesting point made about batteries in a dual configuration becoming electrically unbalanced because the first battery does more work, i.e. more loads, charging cycles and at higher Depth of Discharge (DOD) rates than the second battery.

This also applies to Grenadiers and Quartermasters equipped with the auxiliary battery option because all electrical loads are taken by the starter battery and the auxiliary (2nd, dual) battery supports the starter battery by pulsing a trickle charge to the starter battery via the battery combiner (Smartpass 120S) when the starter battery voltage is below the auxiliary battery voltage.

I raised an enquiry about this with Ctek on Monday and got a response today (Wednesday).
My question was about imbalance, and if this might affect the service life of the 2x EFB in some Ineos vehicles. I also asked if rotating batteries periodically would extend the life of both batteries.
Ctek's response was yes, we should expect the starter battery to fail earlier than the auxiliary battery because of the unbalanced loads, and yes it would be beneficial to swap the batteries around a couple of times each year to maximise the service life of both batteries. One battery is working quite hard and the other is not being worked hard enough.

A battery swap is not a difficult task but it's not made easy due to the under seat trim in 5 seat vehicles and the necessity to let the vehicle go to sleep first. Those inconveniences aside, a biennial swap around might be a worthwhile action.
There's a definite effort required to do this but if it means you're less likely to experience a starter battery fail in service (you'll be remote, on a Sunday, and it'll be raining), then perhaps it's worthwhile.

Food for thought as a preventative maintenance action

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Living in the tropics here in north QLD Australia and previously in far north QLD, most people with 4x4 trucks replace batteries at 2-3 years. The heat and humidity just kills batteries up here. I would never go out on a remote trip with an old battery up here. It’s expensive but less than getting stuck out bush in the heat.

 

[DaveB]

It looks like they have removed the option from the Australian Website... and the Fusilier has reappeared in the vehicle list

I didn't realise the Fuselier had been taken down.
I don't go back to website very much anymore.